Connecting the Dots: US Extended Nuclear Deterrence and Denuclearization of the Korean Peninsula
Extended nuclear deterrence is a key feature of the security framework on the Korean peninsula. Despite hints of a weakening US–South Korean alliance,64 the US commitment to providing extended nuclear deterrence to South Korea still has relevance for peace and security on the peninsula. US conventional and nuclear weapons are still perceived as a threat to Pyongyang – a perception that is reinforced by the presence of US military systems in the region. Despite this, the US extended nuclear deterrent commitment to South Korea appears to have been an inconsistent feature of diplomacy with North Korea. Throughout 2018, inter-Korean diplomacy pushed ahead to take steps in support of improving the security environment and developing peaceful relations between the two Koreas. In parallel, the US–North Korea diplomatic track, tasked with addressing the nuclear issue and in support of improving relations between Washington and Pyongyang through denuclearization, proceeded at a slower pace initially, and both areas of engagement are now stalled. Although the US–North Korea engagement initially included military issues, these were latterly faded out in favour of a reliance on sanctions relief as the prominent offering.
Diplomacy with North Korea offers an opportunity to reduce the salience of nuclear weapons on the Korean peninsula, as well as reducing conventional military risk, and is of course worthy of energetic pursuit. However, denuclearization is not an issue distinct from the US–South Korean alliance. The US military presence in South Korea contributes to Pyongyang’s perception of threat, and, more generally, to the security environment that has in part driven the North’s acquisition of nuclear weapons. Failure to retain this as a central consideration in any negotiation process with North Korea might put limits on how far denuclearization can proceed.
There are three broad components to the extension of US deterrence to South Korea. First, the two states conduct combined military exercises. These exercises are designed to allow the US and South Korean forces to practise interoperability, to maintain readiness in the event of conflict with North Korea, and to prepare South Korean forces for the transfer of wartime operational control. Although US nuclear weapons were withdrawn from South Korea in the early 1990s, under the administration of George H. W. Bush, the joint exercises have included a demonstration of an enduring nuclear commitment to the security of South Korea through the involvement of nuclear-capable aircraft. This is intended as a show of extended nuclear deterrence,65 and has been reiterated through US Air Force bomber runs from Guam in response to North Korean provocations. Although these activities are in part designed to demonstrate resolve and capability to North Korea in support of deterrence, they also play a part in providing assurances to South Korea, and in reminding both Koreas that the US is committed to the protection of its ally. 66 Second, and for similar reasons, approximately 28,000 US troops are stationed in South Korea. Third, to underpin these efforts, during 2016 the US and South Korea also created the Extended Deterrence Strategy and Consultation Group (EDSCG), to improve political coordination and communication in relation to deterring North Korea.67 This, however, is a relatively new initiative that may have suffered from the increased priority given to diplomatic engagement with North Korea in more recent years, rather than public efforts to address the threats its nuclear and missile programmes pose.68
The US–South Korean alliance has been faced with a number of issues related to the extended deterrence commitment in recent years. As North Korea’s capabilities have undergone rapid development under the leadership of Kim Jong-un, there has been a commensurate need for change in the way in which South Korea and the US tailor deterrence. To some extent, the EDSCG is meant to deal with this challenge. In addition, disagreements over the amount to be contributed by South Korea to the costs of the US military presence, as well as over the military pressure brought by the US on North Korea during 2017, and the question of how the alliance should manage Seoul’s desire, under the administration of Moon Jae-in, to pursue an improvement in inter-Korean relations ahead of more concrete steps on the nuclear front, continue to fuel doubts over the health of the alliance.69 This raises questions as to what extent the US and South Korea are currently aligned in their thinking on the role played by extended deterrence on the Korean peninsula, and how they might be able to take a flexible approach in order to foster diplomacy and denuclearization with North Korea.
As North Korea’s capabilities have undergone rapid development under the leadership of Kim Jong-un, there has been a commensurate need for change in the way in which South Korea and the US tailor deterrence.
US extended deterrence has sought to bolster the defence of South Korea as the nuclear threat from the North has developed. This has resulted in a security dilemma, with increased provocations from North Korea leading to a more visible US military presence intended to underscore its commitment to the defence of the South, which in turn contributes to North Korea’s drive to bolster its nuclear weapons capability, which has led to a bolstering of the US military presence, and so on. South Korea’s development of its own advanced conventional capabilities has in recent years also contributed to this cyclical security environment.
Although the US has not stationed nuclear weapons in the South for almost two decades, nuclear and conventional deterrence issues on the Korean peninsula remain connected. The continued presence of the North’s long-range artillery keeping Seoul in clear range may be a reflection of North Korea’s desire to be able to hold Seoul at risk not only in response to inter-Korean tensions and hostility, but also for reasons of leverage and balance in relation to the threat posed by US military capabilities.70 Furthermore, its long-range artillery offers North Korea a quick response asset, especially in relation to superior US air power in the region. The US has regularly demonstrated the latter by flying dual-capable (conventional and nuclear) bombers over or close to the peninsula in so-called ‘deterrence runs’, reminding both its allies and its foes of the extent of its nuclear capability. While these flights are usually conducted in response to a provocation by North Korea, or within the framing of combined exercises with the South (and are therefore referred to as legitimate),71 they remain a cause of concern for North Korea and heighten the threat perception that has helped drive the acquisition of nuclear weapons by Pyongyang.
Attempts were made in 2018 to break the cycle. The Moon administration in South Korea has consciously prioritized broad peace and security in its developing relationship with the North, which has given rise to new efforts to improve the bilateral defence relationship. Most notable is the Agreement on the Implementation of the Historic Panmunjom Declaration in the Military Domain, signed in Pyongyang in September of that year.72 This agreement outlines a series of action points taken – from the creation of no-fly zones to improved communications – in support of transforming hostile military relations with the aim of avoiding any military clashes, accidental or otherwise. Although this remains a bilateral agreement, and its full implementation was called into question in 2019,73 it remains significant in that it recognizes that conventional military issues have a part to play in addressing denuclearization.
However, the most important area where steps have been taken to specifically address the linkage between extended deterrence and denuclearization was the suspension by the US in 2018–19 of large-scale combined military exercises with South Korea, with the stated purpose of fostering an improved atmosphere in support of diplomacy.74
From the perspective of denuclearization, the issue of US extended deterrence to South Korea is a trilateral one; the limits to using provisions that support US extended deterrence to South Korea as concessions in negotiations with North Korea might mean there is a limit to the concessions the latter is willing to make in relation to its nuclear weapons programme. Steps to address broader military concerns have been demonstrated already through the most recent phase of engagement with North Korea in 2018, resulting in efforts to reduce conventional threats and risks in order to create space for engagement on the nuclear front. Although US President Donald Trump suspended the US–South Korea large-scale combined military exercises in 2018 – and the 2019 iterations were reformulated, with small exercises again being cancelled in the interests of supporting nuclear diplomacy – these efforts were subject to criticism from former military personnel and non-governmental experts, and have not been formalized.75 Furthermore, since the US–North Korea summit in Hanoi in February 2019, military issues appear to have been reduced to a lesser factor in denuclearization; sanctions relief has become the primary discussion point for trade-offs with North Korea (should diplomacy move forward); and for the upcoming 2020 iterations of the exercises, reports have already suggested that elements removed or scaled down over the past 18 months may be reinstated as a result of the increased belligerence from North Korea during the latter part of 2019.76
Both North Korea’s nuclear programme and the US–South Korea military alliance form key components of the security context on the Korean peninsula. Addressing the connection between conventional and nuclear military issues on the peninsula will need to remain a prominent feature of the relevant parties’ diplomacy with Pyongyang if long-term and concrete changes to North Korea’s nuclear programme are to be taken seriously. North Korea has hitherto had to make little change to the threat it poses to others, but was able to enjoy the benefit of an improved atmosphere through 2018 and much of 2019. This has bought Pyongyang time in which it has been able to continue to develop its nuclear and missile capabilities.77 But the US and South Korea should be willing to consider both flexibility in how the extended deterrence commitment manifests in reality, and making further amendments to how the extended deterrence relationship works in practice at different stages of denuclearization. Although this process may take time, both the US and South Korea should continue to work to understand how extended deterrence could feature in denuclearization. This entails assessing where changes to the practical elements of the relationship could be made, and what corresponding measures from North Korea might look like. The suspension of US–South Korean large-scale military activities, to create space for diplomacy and reduce the opportunity for miscalculation, along with South Korea’s efforts to improve the inter-Korean military relationship, should of course both be welcomed. Efforts in this regard should be formalized, and military issues should be kept prominent in both the inter-Korean process and that of US–North Korean diplomatic engagement. This must, however, take place in tandem with steps to cap North Korea’s nuclear programme, to restrict North Korea’s ability to create room to ‘decouple’ the alliance, without having to make significant changes to both its conventional and nuclear capabilities that pose risks not just to the peninsula but also further afield.
Without consideration of the bigger picture of the security environment on the Korean peninsula, and the role the US presence and extended nuclear deterrence plays in that, long-term efforts to cap and roll back North Korea’s nuclear programme will likely be limited. The role of nuclear deterrence features prominently in North Korean thought. Connecting the dots between the enduring military concerns on the peninsula and any respective agreements between the US, South Korea and North Korea will be important in ensuring that Pyongyang is not left in a situation where it has taken limited or no steps to constrain its own nuclear programme, yet perceives the US–South Korea extended deterrence relationship as weakened. Without this coordination across engagement, nuclear weapons will continue to cast a shadow over the peninsula.
64 Kim, S. (2018), ‘Troubling signs in US-South Korean alliance’, The Hill, 2 November 2018, https://thehill.com/opinion/national-security/
414407-troubling-signs-in-us-south-korea-alliance (accessed 14 Aug. 2019).
65 For example, see US Department of Defense (2013), ‘Statement by Deputy Secretary of Defense Ashton B. Carter at U.S. Embassy Seoul’, 18 March 2013, http://archive.defense.gov/Speeches/Speech.aspx?SpeechID=1760 (accessed 27 Nov. 2019).
66 Collins, R. (2014), ‘A Brief History of the US-ROK Combined Military Exercises’, 38 North, 26 February 2014, https://www.38north.org/2014/
02/rcollins022714/ (accessed 27 Nov. 2019).
67 US Embassy and Consulate in Korea (2017), ‘Joint Statement on the Extended Deterrence Strategy and Consultation Group’, 5 September 2017, https://kr.usembassy.gov/090517-joint-statement-extended-deterrence-strategy-consultation-group/ (accessed 27 Nov. 2019).
68 Chun, I. (2019), ‘U.S. Extended Deterrence and the Korean Peninsula’s Changing Threat Environment’, Council on Foreign Relations, 29 April 2019, https://www.cfr.org/blog/us-extended-deterrence-and-korean-peninsulas-changing-threat-environment (accessed 27 Nov. 2019).
69 Pardo, R. P. (2018), ‘Will America Lose Seoul? Redefining a Critical Alliance’, War on the Rocks, 5 September 2018, https://warontherocks.com/2018/09/will-america-lose-seoul-redefining-a-critical-alliance/ (accessed 27 Nov. 2019).
70 Varriale, C. (2018), A Long Road to Denuclearisation: Challenges to Security-Based Diplomacy with North Korea, RUSI Occasional Paper, https://rusi.org/sites/default/files/201812_op_security_based_diplomacy_in_north_korea_web.pdf (accessed 27 Nov. 2019).
71 See Yonhap News (2018), ‘Kissinger rejects ‘freeze-for-freeze’ with N. Korea’, 26 January 2018, https://en.yna.co.kr/view/AEN201801
26000200315 (accessed 14 Aug. 2019); Yun, B. S. (2017), Security Council Thematic Meeting on Denuclearization of the DPRK, Remarks by H. E. Yun Byung-se, Minister of Foreign Affairs, 28 April 2017.
72 2018 Agreement on the Implementation of the Historic Panmunjom Declaration in the Military Domain, https://www.ncnk.org/resources/publications/agreement-implementation-historic-panmunjom-declaration-military-domain.pdf (accessed 27 Nov. 2019).
73 Panda, A. (2019), ‘South Korea Expresses ‘Regret’ at North Korean Violation of 2018 Military Agreement’, The Diplomat, 26 November 2019, https://thediplomat.com/2019/11/south-korea-expresses-regret-at-north-korean-violation-of-2018-military-agreement/ (accessed 10 Feb. 2020).
74 US Department of Defense (2018), Press Statement on Military Exercises on the Korean Peninsula, 22 June 2018, https://www.defense.gov/Newsroom/Releases/Release/Article/1558403/press-statement-on-military-exercises-on-the-korean-peninsula/ (accessed 10 Feb. 2020).
75 Denmark, A. M., Ford, L. (2018), ‘America’s Military Exercises in Korea Aren’t a Game’, Foreign Policy, 21 June 2018, https://foreignpolicy.com/
2018/06/21/americas-military-exercises-in-korea-arent-a-game/ (accessed 27 Nov. 2019).
76 Yonhap (2020), ‘S. Korea, US to adjust combined drills for diplomacy with N. Korea: defense ministry’, Korea Herald, 2 January 2020, http://www.koreaherald.com/view.php?ud=20200102000582 (accessed 8 Jan. 2020).
77 Elleman, M. (2019), ‘North Korea’s New Pukgusong-3 Subarmine-Launched Ballistic Missile’, 38 North, 3 October 2019, https://www.38north.org/2019/10/melleman100319/ (accessed 9 Jan 2020).